(a) Technical Field
Embodiments of the present invention relate to an input voltage detection circuit and a power supply including the same. For example, the embodiments relate to a circuit for detecting a zero-crossing or peak of a line input voltage.
(b) Description of the Related Art
A power supply converts an alternating current (AC) input into a line input voltage by rectifying the AC input.
A rectifier circuit of the power supply includes a plurality of diodes and parasitic capacitors are respectively connected to the plurality of diodes in parallel. Also, a Y-capacitor for flowing electromagnetic interference (EMI) noise to a ground is connected between an input terminal of the AC input and the rectifier circuit.
However, distortion of the line input voltage is caused by tolerances of the parasitic capacitor and the Y-capacitor. For example, as the tolerances of the parasitic capacitor and the Y-capacitor are increased, the distortion of the line input voltage is increased.
Thus, there is a problem in that it is difficult to accurately detect a zero-crossing of the line input voltage.
Also, when the power supply has no load or a light load, distortion of the line input voltage may occur in the vicinity of the zero-crossing of the line input voltage. In this case, it is also difficult to detect the zero-crossing of the line input voltage.